The reaction between an organic carboxylic acid and a vicinal epoxide to yield the corresponding .beta.-hydroxy ester is known to be catalyzed by inorganic bases and by amino compounds, e.g. U.S. Pat. No. 2,929,835.
Such a reaction is also known to be catalyzed by compounds containing an ionizable atom of iron or chromium. Illustrative of such compounds is ferric chloride, ferric alcoholates or carboxylates and chromium tribromide, and other like compounds, as described in British Pat. No. 871,767.
The reaction conditions of temperature, pressure, etc., may vary with reactants, but generally, the temperature is between about 60.degree. C. and 130.degree. C., and the pressure is atmospheric or superatmospheric, and the procedure involves mixing the reactants in the presence of a suitable catalyst and then maintaining the reaction mixture at a suitable temperature and pressure until the desired reaction product is formed.